Incident Description
During a flight, the aircraft required full nose-down trim and forward pressure on the yoke to maintain level flight. A logbook entry was made, and subsequent inspection revealed damage resulting from contact between the elevator and rudder.
Inspection Findings
Examination of the elevator gust lock mechanism showed that only three of four elevator stop bumpers were installed. The upper right bumper was missing, although its mount bolt remained in place. The upper left bumper was cracked, chipped, crazed, and displayed a longitudinal crack extending its entire length.
Flight Data Recorder Analysis
Flight data recorder (FDR) data from the previous flight indicated that when the aircraft taxied onto the departure runway, the gust lock was released. This resulted in a rapid deflection of the elevator control surfaces and the control yoke. At the point where the control yoke returned to its nominal position, the left-hand and right-hand elevator graph lines were approximately 4 degrees apart. These lines remained separated by about 4 degrees for the remainder of that flight. In contrast, examination of prior flights showed that the elevator control surface graph lines were superimposed in all modes of flight.
Weather at Departure
Winds at the departure airport were reported from 300 degrees at 22 knots, gusting to 27 knots.
Manufacturer Comment
A product safety representative for the aircraft manufacturer stated that the airplane would have been undamaged during the rapid elevator deflection, had the elevator stop bumpers been properly installed.